The present invention relates to printers that print characters or graphics on tape type print media, and more particularly relates to a tape printer apparatus and control method for controlling a tape cutting means within a tape printer having a tape cutting means.
Two significant problems exist with prior art tape printers as is explained in detail below. The first problem is related to print quality. Gaps are created between the dot strings which comprise a graphic or character symbol when, in a prior art tape printer, during the printing of a symbol, tape feeding is suspended and the tape is cut. Prior cutting means pulled the tape slightly through the print means so that when printing resumed, a larger than acceptable space between dot strings existed. These gaps give rise to undesirably noticeably intrasymbol gaps. The second problem is related to wasted tape. Tape waste arises from the need to advance the tape by an amount large enough to move the printed portion of the tape beyond the cutting means. Because of this tape transfer, the next printed tape will have an excess and unwanted lead portion.
In prior art tape printers blank space, approximately equal to the distance separation the printing means from the cutting means, preceded the printed portion of the tape being printed in order for the printing means and cutting means to be positionally separated. The tape was fed, up to a predetermined position, by the tape feed means after which the tape was cut.
These types of printers have been disclosed in Japanese Patent Early Disclosure H2-147272 (U.S. Pat. No. 4,836,697) and Japanese Patent Early Disclosure S58-500475 (U.S. Pat. No. 4,462,708).
FIGS. 19(a)-(c) illustrate an example of the label making process of a prior art tape printer. In this example, production of a tape piece (i.e. label) printed with the character string "ABC" is shown. In FIGS. 19(a)-(c), P1 is the position of thermal print head 15, P2 the position of the cutting blade, and L is the head-to-cutter distance. FIG. 19(a) shows the state of the tape before printing takes place; printing starts in this state and tape feeding occurs during this printing operation. FIG. 19(b) shows the state where printing has been completed. Next, in this example, the tape is fed to the left a distance substantially equal to L in order to output the tape piece. FIG. 19(c) shows the state where the printed tape has reached tape cutting position P2. When cutting is done, the tape piece printed with "ABC" will be output.
It can be seen that the tape piece output has an excess portion substantially equal to length L in the portion which leads the printed portion (as shown by slanted lines in FIGS. 19(b)-(c)). This excess portion may have to be cut off by some method before using the tape piece as a label. This leads to wasted tape, and the user suffers the nuisance of having to cut off this excess with scissors or the like.
FIG. 20 is a flowchart illustrating the label making process of prior art tape printers. Initially printing is done on the tape (step 401), after which feeding (i.e. advancing or forwarding) of the printed tape is done (step 402) to a length substantially equal to L (i.e. the distance between the printing position and the tape cutting position). Tape cutting (step 403) is done, and the printed piece of tape is output. Next comes a decision (step 404) of whether to repeat the printing. When printing is to be repeated control returns to printing (step 401), and when no further printing is to be done, the process ends (step 405). After outputting the printed tape piece, the work of cutting off the excess portion included in the output tape piece must be done by the user.
This excess portion is generally useless, and resources could be saved and costs reduced if production of this excess portion of tape could be eliminated. In order to accomplish this, it would be good if there were no positional distance between the printing means and the cutting means, but this would lead to difficulties in the mechanism. Therefore a need exists for a way to decrease or eliminate the production of this useless tape.
FIG. 21 shows the distorted dots of the prior art tape printers, showing the print dots when printing is suspended during printing and cutting is done. After printing dot string 207, tape feed is suspended and tape cutting is done. The printed tape is pulled by the cutter in the tape feed direction during the cutting process. This means that the distance between the dots of print string 208 and print string 207 will be greater than the distance between the other dot strings, and because of this there is a gap, or space, between print strings. The difference between the distance d1 between dot strings of conventional printing 206, 207 and the distance d2 between dot strings before and after tape cutting 207, 208 is about 0.05 mm. A gap of this size, shown by arrow D in FIG. 21, can be clearly seen on a printed tape. Consequently, special control is necessary so that the tape cutting process can be done without adversely affecting the quality of subsequent print strings.
Further, although prior attempts have been made to cut recording paper in the course of printing, they lacked practicality because of problems related to the recording paper shifting during cutting and producing gaps in the resultant printing.